Virtual reality (VR) is a rapidly developing area of technology in which video content is provided to a VR display system. As is known, a VR display system may be provided with a live or stored feed from a video content source, the feed representing a VR space or world for immersive output through the display system. In some embodiments, audio is provided, which may be spatial audio. A virtual space or virtual world is any computer-generated version of a space, for example a captured real world space, in which a user can be immersed through a display system such as a VR headset. A VR headset may be configured to provide VR video and audio content to the user, e.g. through the use of a pair of video screens and headphones incorporated within the headset. Position and/or movement of the user device can enhance the immersive experience.
VR sickness may occur when exposure to a VR space or world causes symptoms similar to motion sickness. It has been theorized that this is at least partly due to the disagreement or disconnect between what the user sees and what the stimuli from the inner ear are sending to the brain. It may be particularly prevalent if the VR camera is moving during image capture.
Video stabilization techniques may be employed to avoid such effects. In general these may employ active mechanical systems for compensating the different camera motions in real time, and may be combined with content-stabilising image processing. For example, a camera gimbal may be used. A gimbal is a mechanical, typically motorised, external device for camera stabilization which aims to compensate for rotation around three axes. It has disadvantages in terms of its size, weight, power consumption, latency, noise and cost. It is considered less attractive for VR cameras where a panoramic or 360 degree field-of-view is required. This is because the gimbal may enter the field-of-view. In general, mechanical stabilization setups also have a limited compensation range, e.g. due to using servo motors, and image processing methods are often needed in addition. Even then, where there is rotational movement, known stabilization methods tend to cause distortion.